X-ray tomography entails the multiple X-ray photographing of an object from the sides in order to derive, by computer, a view from the top. However, when it is desired to increase the resolution of the tomography, i.e., to see smaller parts of the object, numerous problems are encountered.
For example, one problem results from the type of detector used in X-ray tomography. X-ray film is not used because the cost would be prohibitive (because of the multiplicity of photographs needed) and also because it is difficult to transfer data from such a detector (i.e., film) to a computer. Instead, the detectors actually used are generally small, discrete sensors which respond to x-radiation. In order to achieve increased resolution, smaller sensors must be used, packed closely together. Clearly, there arise problems in manufacturing very small sensors which are spaced very close to each other.
Apart from manufacturing challenges faced in the manufacture of high resolution tomography sensors, many of the prior art tomography apparatus function well only in controlled environments. Applicants have discovered improvements which eliminate the necessity of maintaining a controlled environment and which allow such tomograph apparatus to be implemented in an abusive environment, such as at a manufacturing site, and, further, to be used on a continual, uninterrupted basis. Such improvements have significant relevance to the tomographic examination of gas turbine engine parts, including turbine blades.
In addition, one form of prior art ionization detector utilizes baffles 3A positioned between adjacent detectors 6A as shown in FIG. 1. The baffles function to prevent an ionized particle 9A from following a path 12A and thus falling upon a detector other than the detector directly beneath it, namely, detector 6B.